Abstract: A fixing unit or device that can be used in an image forming apparatus includes a first heater element that is formed of a material that increases in electrical resistance with increases in temperature. A controller of the fixing unit is configured to vary a duty ratio of electric power applied to the first heater element during a start-up operation in which the temperature of the first heater element is raised to a target operating temperature. By varying the duty ratio during the start-up operation, changes in the resistance of the first heater element with the heating can be compensated. For example, the duty ratio can be increased during the course of the start-up to achieve the target operating temperature faster.

Abstract: A degassing apparatus for a metal mold comprises a valve body and a bypass. The valve body is slidably provided between an end of a vent groove communicating with a metal mold cavity and a valve opening/closing portion before an exhaust hole. When a molten metal flowing from the cavity acts on a surface of the valve body, the valve body moves toward the exhaust hole and blocks a path toward the exhaust hole. The bypass bypasses a valve head of the valve body from the vent groove and guides gas to the exhaust hole. The valve head of the valve body has a substantially head-cutting conical outer shape projecting in the direction of the vent groove. The vent groove has a gas vent path extending from a top portion to the vicinity of the base of the valve head along an outer surface of the valve head. An end portion of the gas vent path corresponding to the base of the valve head communicates with a start portion of the bypass which bypasses the valve head.